Treatment of artificial fibrous material



Patented May 14, 1935 UNITED STATES TREATMENT OF ARTIFICIAL FIBROUS MATERIAL Leon Lilienfeld, Vienna, Austria No Drawing.

Serial N0. 308,589. ber 21, 1927 19 Claims.

amount by treating the artificial fibers with an alkali solution and carbon disulphide.

The invention, which consists in a treatment of artificial fibers with these reagents, is applivery much more than this figure.

cable to artificial fibers, especially artificial silk, which consists of or contains cellulose or cellulose hydrate, for example, to viscose silk, cuprammonium silk and nitrate silk. In referring to viscose silk in this specification, I embrace any and all silk (or fibers, threads, etc.) made from viscose by the use of any of the precipitating agents known. The process is of especial technical importance in its application to artificial fibers (hereinafter called fiasticized artificial fibers) which are distinguished by a high strength,

for example to artificial fibers which can be made by spinning viscose in a spinning bath consisting of or containing a strong mineral acid, particularly strong sulphuric acid, as described for example in my U. S. patent applications 113,582 and 113,583 filed June 3, 1926 and'156,751 filed December 23, 1926, (which applications have now matured into Patents 1,820,811, 1,683,200 and 1,683,199 respectively, the latterreissued as No. 18,170).

It is inherent in the products of my copending cases here referred to, that they possess high dry and wet tenacities, for example a dry tenacity exceeding 2 grams per denier, and in many cases However an objection to these products is the fact that they have only a low degree of extensibility (usually not over 4 to 5% and in any observed case not substantially over 7%) and a low degree of elasticity, both in fact considerably lower than ordinary good grade viscose silk. I

By a strong mineral acid, or strong sulphuric acid (as herein referred to) is to be understood a mineral acid, the mineral acid content, for instance the sulphuric acid content of which, corresponds with that of a sulphuric acid containing at least 50 per cent of H2804. The acid can also be stronger, e. g. 70% H2804, more or less, see

above cases.

The artificial fiber may be treated with an alka:

li solution and with carbon disulphide simultaneously, or separately with these reagents, in either order. That is to say, the fiber may be treated first with an alkali solution and then with carbon disulphide, or first with carbon disulphide and then with an alkali solution, or it may be treated with a mixture of carbon disulphide and an alkali solution, which mixture may be an emulsion of carbon disulphide in the alkali solution.

It is of importance that the treatment with Application September 26, 1928, In Great "Britain Novem alkali solution and carbon disulphide should be such that the artificial fibers are not subjected to xanthogenation in too great a degree, that is to say to such a degree that they would dissolve or swell to too great a degree, or disintegrate during the treatment. In order to avoid too intense a treatment, the duration ofthe action of the carbon disulphide in presence of alkali should be suitably selected, and should not be too prolonged, or the strength of the alkali solution should not be too high. The danger that the artificial fibers may undergo dissolution or excessive swelling is very slight if the fiber is first ed with an alkali solution, or if the fiber is treated with a mixture, for example an emulsion, of carbon disulphide and alkali solution.

It is preferable to conduct the treatment in such a manner, that the fibers are not subjected to tension, or are subjected only to moderate saturated with carbon disulphide and then treattension: if, however, considerable tension be applied during any part of the treatment, it is desirable that the tension should be relieved or diminished at some moment at which a subsequent shrinkage of the fiber still appears possible, preferably before the fiber leaves the alkali solution. or before washing out the alkali.

The artificial fibers may be subjected to the treatment in accordance with the invention whilst they are in the dry state, 'or whilst they are moist, or wet: thus the invention may, if desired, be introduced into the spinning process, in which case the treatment may be applied to the fibers which leave the spinning bath, or after they leave the bath (for instance water), if any, in which the bobbins rotate, or after the washing operation.

Artificial fibers, and in particular fabrics consisting of or containing artificial threads, when treated in accordance with this invention, not only acquire an increased extensibility and elasticity, but their tendency towards creasing is much reduced and in some cases may be wholly or nearly wholly eliminated.

The invention is applicable not only to artificial fibers, for example artificial silk, as such (whether in the form of threads, yarn or skeins or-cops, or in the form of warps) but also to artificial fibers (such as artificial silk or staple fiber) in the form of woven material. It is also applicable to fibers or fabrics consisting either,

is to say, to threads or fabrics containing besides a an artificial fiber another fibrous material, such as cotton, natural wool or natural silk. It is to be understood that the expression artificial fibers of regenerated cellulose" as used in this specification is intended to include for example,

artificial silk, artificial wool, artificial cotton, artificial hair or. other kinds of artificial fiber, in any of the forms as aforesaid and of the kinds hereinbefore stated.

The following examples illustrate the invention:'-

Example 1 Viscose silk made by the process described in application No. 156,751, (which involves the treatment of the freshly formed viscose silk with H2804 of 50% strength, or more, or other acid of equivalent strength), in the form of dried finished (but if desired, unbleached) skeins, is impregnated preferably at room temperature, with carbon disulphide without application of tension, for instance by passing it through a bath containing carbon disulphide, by immersing it in carbon disulphide, or by spraying it with carbon disulphide. The carbon disulphide may be used in undiluted form, or in conjunction witha suitable diluent, such as benzene or the like.

The duration of the treatment with carbon disulphide may be selected as desired. Generally, the yarn absorbs the requisite quantity of carbon disulphide even during a period of from a few seconds up to two minutes, so that a short impregnating treatment is as a rule sulficient. The yarn impregnated with carbon disulphide, if desired after separating the excess of carbon disulphide by pressing; centrifuging or the like, is then introduced into a caustic soda solution of 18-20 per cent strength and preferably at a temperature of 15-18 0., and allowed to remain in this soiutior for 1-5 minutes.

After removal from this bath, the yarn is freed,

if required, from'excess of caustic soda solution by pressing, centrifuging or the like (say at room temperature), and is then introduced into sulphuric acid of 5-10 per cent strength, or into any other precipitating bath known in the viscose industry, for example a solution of ammonium sulphate of 10-25 per cent strength, hydrochloric acid of 4 per cent strength, or the known-Muller bath or the like. These treatments may be performed at room temperature. After the yam has been allowed to remain in the precipitating bath for a short time, it is removed, then washed and finally dried.-

The silk, which prior to the treatment above described, showed an extensibility of 4-5 per cent, shows after the treatment an extensibility of 13-18 per cent, whilst its elasticity, which was originally 3.5-4 per cent, is increased by the treatment to 5-6 per cent. The lustre oi the silk does not suffer or sufiers only moderately from the treatment.

' Example 2 Example 3 The procedure is as described in Example 1 m Example 2 with the modification that there s used a caustic soda solution of '10 per cent strength, kept at a temperature of 0 to ---5 0.

Example 4 The procedure is as described in Example 1, Example 2 or-Example 3, with the modification that the artificial silk is washed with hot or cold water after the treatment with the caustic alkali solution and before it is introduced into the precipitating bath.

Example 5 Artificial silk in skeins, as used in the preceding examples, is introduced, without applying tension, into an emulsion or mixture, made in known manner of carbon disulphide and caustic soda solution of 18 per cent strength (for example consistingot 10 parts by weight oi' carbon disulphide and 90 parts by weight of the caustic alkali solution), and allowed to remain in this emulsion or mixture for 2 to 10 minutes whilst the temperature is maintained at 15-20" C.

The material is thentreated with acids or the setting baths of the viscose industry, in the manner prescribed in Example 1 for the treatment of the material after its removal from the alkali solution in that example.

Example 6 Artificial silk in skeinsms used in the preceding examples is introduced, into a caustic soda solution of 18-20 per cent strength at a temperature of 15C., allowed to remain in this solution for about l-5 minutes, and is then removed Example 7 Mode of operation as in Example 6, with the exception that the strength of the caustic soda solution is 5 per cent only.

The precedure described in the foregoing examples may be varied, for instance, by using another agent capable of precipitating viscose for ek-- ample steam, instead of the precipitating agents therein named, and by using ordinary viscose silk of any kind, or copper silk (i. e. silk made from cuprammonium solution of cellulose) or nitrate silk, instead of the viscose silk specified therein.

The treatment described in the foregoing examples may also be applied to artificial silk whilst the latter is in the stretched condition, or whilst it is subjected merely to a moderate tension: care should, however, be taken to discontinue or diminish the tension before the material is removed from the alkali solution.

The procedure for the treatment of fabrics, or of yarn containing besides artificial silk another fibrous material, such as cotton, follow from the examples which have already been given.

In the appended claims, I use the term successive to mean that the two reagents are employed one after the other, and not as intending to imply that the treatment with alkali solution must come before the treatment with carbon disulphide. And in said claims I use the term Joint to cover the use of the several materials referred to in said claims, whether they are used simultaneously or successively (in any desired order) The expression "artificial cellulose fibers" is 76 intended to include all artificial fibers consisting of, or containing cellulose or cellulose hydrate, that is, artificial fibers made from viscose, for example viscose silk, artificial fibers made from solution of cellulose in cuprammonia, for example cuprammonia. silk and denitrated cellulose nitrate artificial fibers, for example nitrate silk.

1. A process for increasing the extensibility and contraction of artificial fibers of regenerated cellulose, wherein the artificial fibers are treated with an alkali solution and carbon disulphide in any order and permitting shrinkage of said material to occur.

2. A process as referred to in claim 1, wherein the artificial fibers are treated in substantially unstretched condition.

3. A process as referred to in claim 1, wherein the artificial fibers are in a stretched condition during only a portion of the treatment, but the stretching is at least partially relieved before the fibers leave the alkaline bath.

4. A process as referred to in claim 1, applied to viscose silk which has been made by spinning viscose in a bath which contains mineral acid of a strength corresponding to at least 50% of sulphuric acid.

5. A process for increasing the extensibility of artificial fibers of regenerated cellulose, which process comprises thestep of subjecting the artificial fibers while not in a strongly stretched condition to the joint action of an alkali solution and carbon disulphide and permitting shrinking of the said material to occur.

6. A process for increasing the extensibility of artificial fibers of regenerated cellulose, which process comprises subjecting the artificial fibers to the joint action of an alkali solution and carbon disulphide and subjecting the fibers to tension during a part only of the entire process which includes said treatment and subsequent washing of the fibers.

7. A process of making artificial silk which comprises the steps of spinning viscose into a bath containing a mineral acid of a strength equivalent to not below 50% of actual sulphuric acid, and subjecting the spun silk to the joint action of an alkali solution and carbon disulphide and permitting shrinking of the said material to occur.

8. A process of making artificial silk which comprises the steps of spinning viscose in a bath containing not substantially below 50% of sulphuric acid and subjecting the spun silk to the joint action of an alkali solution andcarbon disulphide and permitting shrinking of the said material to occur.

9. A process of making artificial silk which comprises the steps of spinning viscose and subjecting same to a bath containing not substantially below 50% of sulphuric acid and subjecting the spun silk to the joint action of an alkali solution and carbon disulphide and permitting shrinking of the said material to occur.

10. A process of making artificial thread which comprises the steps of spinning viscose in a bath which consists of mineral acid having a strength equivalent to at least 50% H2804, and subjecting the spun thread to the joint action of an alkali solution and carbon disulphide without substantially stretching during the latter part of such treatment.

11. A process of making artificial silk which comprises the steps of spinning viscose in a bath which contains not below 50% of sulphuric acid and subjecting the spun silk to the joint action of an alkali solution and carbon disulphide without substantially stretching during the latter portion of the treatment with alkali solution and carbon disulphide.

12. A process of making artificial silk which comprises the steps of spinning viscose, subjecting same to action of a bath containing mineral acid in amount equivalent to at least 50% of H2804, and subjecting the silk to the successive action of an alkali solution and carbon disulphide in any desired order and permitting shrinking of the said material to occur.

13. A process of making artificial thread which comprises the steps of spinning viscose in a bath which consists of sulphuric acid of at least 50% strength, subjecting the thread to the joint action of an alkali solution and carbon disulphide and avoiding substantial stretching during the latter portion of the treatment with alkali solution and carbon disulphide.

14. A process of treating such artificial cellulosic fibers as have a dry tenacity exceeding 2 grams per denier and which in their untreated condition have a relatively low degree of extensibility, which comprises treating such artificial fibers with an alkali solution and carbon disulphide, such steps being in any desired order and permitting shrinking of the said material to occur, whereby the extensibility is increased.

15. A process of treatingsuch artificial cellulosic fibers as have a dry tenacity exceeding 2 grams per denier and which is their untreated condition have an extensibility not substantially exceeding 7%, which comprises treating such artificial fibers with an alkali solution and carbon disulphide, such steps being in any desired order 'and permitting shrinking of the said material to occur, whereby the extensibility of the fibers is increased.

l6. A process for increasing the extensibility of regenerated cellulose fibers having a. dry tenacity over 2 grams per denier, wherein the artificial fibers are treated with an alkali solution and carbon disulphide in any order and permitting shrinking of the said material to occur.

17. A process for increasing the extensibility of regenerated cellulose fibers having a dry tenacity over 2 grams per denier, which process'comprises the step of subjecting the artificial fibers to the joint action of an alkali solution and carbon disulphide and permitting shrinking of the said material to occur.

18. A process for increasing the extensibility of regenerated cellulose fibers having a dry tenacity over 2 grams per denier, which process consists in subjecting the artificial fibers to the successive action of an alkali solution and carbon disulphide and permitting shrinking of the said material to occur.

19. A process for increasing the extensibility I LEON LILIENFELD. 

